Ornamental transfers and indicia presenting heat activated decoratives which have various indicia are well known and are typically applied to cloth and other substrates, particularly clothing. These decoratives, particularly heat activated decoratives, are used to provide numbers on sports jerseys, names on shirts and company logos on uniforms.
There are several types of heat activated decoratives. These have a hot melt adhesive layer which bonds to a cloth substrate. A second, upper layer can be formed of a variety of different materials including thermoplastics, thermosets, flock, and plastisols. In other applications, thread in the form of an embroidered letter can be the upper layer with a thermoplastic adhesive layer on the bottom. These are all applied to a substrate by heat, pressure and time sufficient to melt the hot melt adhesive layer and permit penetration of the melted adhesive into the surface of a garment. Other decoratives ar formed from thermosetting resins which can be cured as they are applied to the substrate.
There are many different types of transfers disclosed in the literature. For example, Liebe U.S. Pat. No. 3,660,212, discloses a heat activated transfer formed of a polyvinyl chloride lower layer and a surface layer of a cross-linked polyvinyl chloride plastisol. The plastisol is highly pigmented and it acts as an ink.
Another decorative is disclosed in Mahn U.S. Pat. No. 4,390,387. This patent discloses a flocked decorative with a lower thermoplastic layer. Further, Mahn U.S. Pat. No. 4,610,904, discloses a heat activated removable ornamental transfer which includes a lower thermoplastic layer and an upper continuous layer of a thermoset material. The upper layer is preferably a thermoset ink. To apply such a transfer, a heat source is applied against the composite. This is pressed against a cloth substrate causing the softened thermoplastic to flow into the cloth and to adhere. The upper layer, as disclosed in this patent, is a continuous layer which stands between the heat source and the thermoplastic layer. A silicone coated sheet can be placed between the heat source and the thermoset layer.
Embroideries which have a thermoplastic layer are usually formed by stitching thread into a scrim fabric. A thermoplastic layer is then laminated thereto. This is then heated and excess thermoplastic material can be removed with an absorbent material such as blotting paper. However, this is applied to a garment by applying heat and pressure directly against the threading which in turn heats up the thermoplastic layer allowing it to be applied to a substrate. Blotting paper is not used in any way to apply the embroidery transfers to a cloth substrate.
The problem with the heat activated film transfers such as the ones disclosed in the Mahn reference is that there must be a continuous upper thermoset layer above the thermoplastic layer. If there is not such an upper, continuous thermoset layer, thermoplastic material will mar the substrate and the heating surface. This presents a problem if one wishes to have a transfer which has a plurality of discrete indicia separated by voids. An example of such a transfer is a person's name which is not resting on a solid background.
It is of course known that one can take a solid laminate that has a continuous thermoplastic layer on the bottom and a continuous thermoset layer on the top and cut these into letters. However, this is expensive, not always precise and impractical for small letters. It would be much more desirable to simply print the indicia bearing thermoset layer using a printing process and without cutting. However, according to present techniques, this would require precise alignment of a thermoplastic layer below a thermoset layer. Even with precise alignment, it is still likely that during application some of the thermoplastic layer will exude from under the thermoset layer marring the transfer.